mirror of
https://github.com/priyanshujain/sanderling.git
synced 2026-10-02 19:17:10 +00:00
pj
ca92bb1492
Six message types: HELLO, PAUSE, RESUME, STATE, EXTRACT_RESULT, GOODBYE. 4-byte big-endian length + JSON payload. 16MB frame cap. Typed constructors per message; snapshots carry json.RawMessage so downstream goja evaluation sees exact types.
108 lines
3.0 KiB
Go
108 lines
3.0 KiB
Go
package agent
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import (
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"encoding/binary"
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"encoding/json"
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"errors"
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"fmt"
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"io"
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)
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type MessageType string
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const (
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MessageTypeHello MessageType = "HELLO"
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MessageTypePause MessageType = "PAUSE"
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MessageTypeResume MessageType = "RESUME"
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MessageTypeState MessageType = "STATE"
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MessageTypeExtractResult MessageType = "EXTRACT_RESULT"
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MessageTypeGoodbye MessageType = "GOODBYE"
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)
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const MaxFrameSize = 16 * 1024 * 1024
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type Message struct {
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Type MessageType `json:"type"`
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ID uint64 `json:"id,omitempty"`
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Version string `json:"version,omitempty"`
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Platform string `json:"platform,omitempty"`
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AppPackage string `json:"app_package,omitempty"`
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Snapshots map[string]json.RawMessage `json:"snapshots,omitempty"`
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Extractor string `json:"extractor,omitempty"`
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Result json.RawMessage `json:"result,omitempty"`
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Error string `json:"error,omitempty"`
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Reason string `json:"reason,omitempty"`
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}
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func Hello(version, platform, appPackage string) Message {
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return Message{Type: MessageTypeHello, Version: version, Platform: platform, AppPackage: appPackage}
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}
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func Pause(id uint64) Message { return Message{Type: MessageTypePause, ID: id} }
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func Resume(id uint64) Message { return Message{Type: MessageTypeResume, ID: id} }
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func State(id uint64, snapshots map[string]json.RawMessage) Message {
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return Message{Type: MessageTypeState, ID: id, Snapshots: snapshots}
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}
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func ExtractResult(id uint64, extractor string, result json.RawMessage, extractorError string) Message {
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return Message{
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Type: MessageTypeExtractResult,
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ID: id,
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Extractor: extractor,
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Result: result,
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Error: extractorError,
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}
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}
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func Goodbye(reason string) Message {
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return Message{Type: MessageTypeGoodbye, Reason: reason}
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}
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func WriteMessage(writer io.Writer, message Message) error {
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payload, err := json.Marshal(message)
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if err != nil {
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return fmt.Errorf("marshal: %w", err)
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}
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if len(payload) > MaxFrameSize {
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return fmt.Errorf("frame of %d bytes exceeds maximum %d", len(payload), MaxFrameSize)
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}
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var header [4]byte
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binary.BigEndian.PutUint32(header[:], uint32(len(payload)))
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if _, err := writer.Write(header[:]); err != nil {
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return fmt.Errorf("write header: %w", err)
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}
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if _, err := writer.Write(payload); err != nil {
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return fmt.Errorf("write payload: %w", err)
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}
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return nil
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}
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func ReadMessage(reader io.Reader) (Message, error) {
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var header [4]byte
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if _, err := io.ReadFull(reader, header[:]); err != nil {
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return Message{}, err
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}
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length := binary.BigEndian.Uint32(header[:])
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if length > MaxFrameSize {
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return Message{}, fmt.Errorf("frame of %d bytes exceeds maximum %d", length, MaxFrameSize)
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}
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payload := make([]byte, length)
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if _, err := io.ReadFull(reader, payload); err != nil {
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return Message{}, fmt.Errorf("read payload: %w", err)
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}
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var message Message
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if err := json.Unmarshal(payload, &message); err != nil {
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return Message{}, fmt.Errorf("unmarshal: %w", err)
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}
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if message.Type == "" {
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return Message{}, errors.New("missing type")
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}
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return message, nil
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}
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